If you don't have any air coming out when you bleed it, and you have checked to make sure there are NO external leaks of brake fluid when you repeatedly activate the brakes, it sounds like you have a bad brake master cylinder.

They're not that expensive, but make sure that you follow the master cylinder bleeding procedure before you even install it on the vehicle, and then bleed the entire sustem after you've installed it.

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.